Not Another One
by TheObserved
Summary: John finds himself in an uncomfortable position when a new Holmes comes to stay.
1. Chapter 1 - An Unexpected Visitor

**Well, this is my first ever attempt at writing fan fiction. I'll have more chapters up soon. I'd love to hear some feedback!**

It was an entirely normal day at 221B Baker Street. John Watson was nibbling at his toast, which was unfortunately missing its jam due to the fact that his lovely flatmate had chosen it as a perfect place to store an eyeball. Mrs. Hudson could be heard downstairs cleaning up an unfortunate accident during a recent case. The telly was relaying the daily news, which Sherlock Holmes was correcting with every story. The only thing that struck John as odd was Sherlock.

Every so often, he would pull out his cell and check it for new messages, glance at his watch, comment on how he needed to clean, and return his focus to the news. The first twenty times John didn't think too much of it. Sherlock _was_ usually strange. After that, though, he had to assume something was up. "Were you going to clean then or...?"

Sherlock gave him a look that said he didn't even realize Watson was there. "Yes, yes. I'm getting to it now," he muttered as he pushed himself out of his chair and disappeared into the kitchen.

John did his best to ignore the commotion that was rising over the telly, but there were some rather concerning noises his ears picked up. Glass breaking, chairs falling, a blender, water splashing. Finishing off his toast, he carried his plate in as an excuse to survey the situation.

He was not prepared to see a garbage bag full of body parts, a nearly empty refrigerator, the table set with place mats, some sort of suspicious fruit smoothie that John didn't remember having fruit for, and a wet floor he nearly slipped on. "Sherlock!" he exclaimed as he steadied himself on the wall. "What in God's name is going on?" For as long as they'd lived together, John couldn't recall a single instance of Sherlock being tidy unless it involved one of his experiments. Even then, though, he wouldn't use the word tidy at all. It was actually more chaotic or terrifying when Sherlock experimented with anything. John and Mrs. Hudson were the ones that always cleaned up his messes, otherwise they would just sit until the dissolved into nothing at all...if that were even possible.

Without breaking his 8 patterns with the mop, Sherlock got out a hasty reply that baffled John nearly as much as the cleaning. "My sisters on her way to visit. Mycroft should be dropping her off any time now."

John furrowed his brow, set his plate in the sink carefully and studied Sherlock for a very long time. "You have a sister?" he finally asked. John didn't know how he felt about that. Sherlock was...Sherlock. And Mycroft was...well, Mycroft. What would Miss Holmes be like and why had he never heard of her before? Was she just as unbearably intelligent as her brothers? Some sort of high achieving, successful woman who didn't have time to be a presence in her family's life? Did they also have a strained relationship? Judging by the way Sherlock was out of sorts about her visit, he began to assume that she was either intimidating for Sherlock or he actually held her in high regards and wanted things to look nice for her.

"My little sister, Ilsa. I haven't seen her since she moved out of our mother's house a few years back." He returned the mop to its bucket and glanced quickly around the room. "Flowers...John! I'll be right back!" And before John had time to respond, Sherlock had his coat and scarf on and had disappeared out the door.

John rushed after him and looked out his door to see Sherlock's dark coat whipping down the stairs. "What am I supposed to do if she gets here and you're gone?!" he called after him, really beginning to worry.

"Don't worry!" was the only thing he got in response.

Don't worry? Don't worry! Of course he was going to worry! Sherlock was practically in a panic to get things ready for her, which is _completely_ out of character for him. He was still wearing his pajamas and robe and Sherlock had left the building! He knew absolutely nothing about the woman except for the fact that she's younger than Sherlock, hasn't seen him in years, and has enough persuasion over him to make him run out for _flowers._ John decided quickly that he needed to get ready as well and rushed off to take a shower.

As he wrapped himself back up into his robe and grabbed up his pile of dirty clothes to hurry off to his bedroom, he heard more of that rummaging in the kitchen again. "Sherlock!" he called as he moved towards the kitchen. "Make sure you get rid of that bag of body parts- Oh, hello there!"

Pale skin, short, choppy brunette hair, and horribly familiar blue eyes were looking him up and down with far too much curiosity for his comfort. John took a few quick steps back, retreating towards his bedroom, but it was too late. "Either a lot has changed or you're not my brother. I'm Ilsa," she chuckled as she strode towards him and grabbed his hand to shake it.

"Well...I..uh-" John stuttered as he tried to escape.

"John! Is she here? I just saw _what are you doing?_" Great. Sherlock had chosen now to show up. The scowl on his face told John that he should not be wearing nothing but a bathrobe to introduce himself to his little sister and for the millionth time John wished he'd just gone straight to his bedroom.

Ilsa didn't seem phased by it, though. The petite woman turned and beamed before rushing over to her big brother and embracing him tightly. The anger seemed to melt right off Sherlock's face as he held her back. "I got you these," he muttered, extending the slightly crushed tulips to her.

If she noticed their condition, she didn't show it and held them to her nose happily. "They're beautiful. Thank you Sherlock!" She gestured to John with a shake of her head. "This your boyfriend? He's awfully cute, you know. If I were you-"

"No! Nope, no, uh uh," John interjected quickly before this could continue any further. "For the record, I am _not_ Sherlock's boyfriend. I am not even gay. I am his _flatmate, _John Watson."

The young woman giggled and nudged her brother. "Not bad."

John groaned and turned on heel. Why did this keep happening? He'd much rather deal with this when he had pants on.

* * *

Now donning jeans and a comfy sweater, he felt a little braver about going out to meet this mystery relative of Sherlock's. Only a little bit, though. From their brief encounter she seemed...perkier than her brothers. But the way those damned blue eyes had picked him apart in seconds... Another shudder racked through his body. He didn't even want to think about what kinds of private...intimate things she had figured out about him so quickly. John pulled at the bottom of his cream colored sweater, nervously straightening it before stepping back out into the living room to be scrutinized again.

"Stop!" John practically jumped out of his skin in surprise. Ilsa had taken up a spot on the sofa and was shooting glances back and forth between a book in her lap and John in the doorway. It seemed perfectly normal until she cracked a mischievous grin and held the book up to Sherlock who was standing behind her.

"What is it? What happened?" John asked rather breathlessly as he searched for danger around him. Sherlock nodded with approval and motioned for John to join them, which he did so apprehensively. Sherlock turned the old, leather-bound book for John to look at. "Is that...Is that me? How did you do this?" It was a sketchbook with an oddly accurate ink sketch of John himself standing in the exact same doorway he'd just walked through wearing his jeans and his sweater. He didn't understand how she managed to have this drawn considering she'd never seen his outfit before and had seen him for less than a minute at their meeting.

Ilsa stretched her arms and laid on her back casually. "Told you I could do it," she teased Sherlock.

"Yes, yes," he sighed as he moved into the kitchen.

"Um, excuse me? Told him you could do what?" John asked, really wishing he wasn't being ignored. He sat heavily in his armchair as he stared at the picture before him. It was completely accurate, down to the part in his hair and the concerned wrinkles in his forehead. It was brilliant, of course, but he shouldn't have expected any less from a Holmes. He just wasn't planning on that brilliance to be so...artistic.

He thumbed a page back and was met with the book slamming shut and being snatched from his grip before he even knew what was going on. Ilsa stood in front of him, clutching the book to her chest protectively. "I told him I could draw what you'd look like walking back in the room."

"Let my guess," John sighed as he sat back, feeling altogether too close to her black leggings and striped blue and purple sweater dress than was proper. "You have a staggering ability to observe and remember things, just like your brother, don't you?"

This made her laugh and John took note of how much better her humor was than either of her brothers'. "Yeah, sure. Something like that," she responded, throwing a glance towards the kitchen. Determining Sherlock was still busy with something or other, she leaned forward and pressed her lips to John's ear and whispered, "I only waste my energy on things I like." With a coy smile she pulled away and sat back on the couch, leaving John's poor mind reeling. For fuck's sake! What was going on?!

**There's my first chapter! Remember I'd love to get some feedback from you lovely readers before I come out with a new chapter. :)**


	2. Chapter 2 - A Nice Walk

**Here's the second chapter! Thanks for the reviews.**

Sherlock strutted back into the room in his usual manner carrying an actual, normal platter of little cheeses and sausages and crackers. He took one look at the expression on John Watson's face and glared at his sister. Setting the tray down, he took a seat in his own armchair and began the interrogation. "What did you do to him?" He steepled his fingers under his chin as he looked back and forth between the two of them like they were co-conspirators.

Swallowing hard, John took the opportunity to stuff a cracker in his mouth. He chewed mechanically as he tried to look as innocent as he could. _He_ hadn't done anything. It was that young woman sitting on the sofa with a smile pulling at her lips. _Ilsa._ What had she meant "_I only waste my energy on things I like"_? That wasn't just something you seductively whisper into a bloody stranger's ear!

"I don't know what you're talking about," she practically purred as she took a cracker herself. "I haven't done anything at all."

"So he's red-faced, manually controlling his breathing and glaring at you for no reason?" Sherlock rolled his eyes as he undoubtedly figured out that his sister had said something completely out of line. "Ilsa, behave yourself or I'll have Mycroft pick you up. John isn't a toy, even if he is as malleable as putty."

"Sherlock," she whined like the manipulative little sister she was. "You wouldn't kick me out for some harmless fun. God knows how long it'll be until we see each other again. Besides, if he's good enough to keep up with you, he _must_ have something interesting about him. Why didn't you tell me about him?"

"Because I knew..._THIS_ would happen!" Sherlock motioned between the two of them, again, like they were both involved in a scandal.

Why did they always talk about him like he wasn't even there? "Um, excuse me. I'm going to go out for a bit. You two can sort this out without me, it appears. I'll just get going..." He was almost to his coat when he was stopped by Sherlock.

"Do us a favor and pick up some things for Ilsa. What was it you forgot?" Great. Always the task monkey for Sherlock and now Ilsa. He turned around with a scowl and was surprised to see her jump up off the couch and pull her own coat and purple scarf on.

At the look her brother gave her, she responded coolly, "Oh don't worry about it. I know what I need. I'll just come with you! It would be good to get an idea of the surrounding area if I'm staying here. I don't plan on being cooped up in here all day and night."

Sherlock's narrowed eyes said he didn't fully believe her. Not at all. "I'm coming with."

"Oh no you aren't," Ilsa snapped at Sherlock, who looked extremely conflicted for once. "For God's sake, Sherlock, I'm a grown woman. You don't think I've managed to travel the globe on my own without being raped by pure luck, do you? Calm down and get supper going. I don't just live off of cheese and crackers, you know." And before he had time to respond, she was out the door and trotting down the stairs with her head held high and no doubt that Sherlock would stay put.

The two men shared an awkward look. "She's tenacious, isn't she?" John offered before he was waved off.

"Go on or you'll never keep up with her," Sherlock grumbled. "You really have_ no_ idea."

* * *

John glanced left, right, left, right. No Ilsa. Shit. Would she really just wander off into the city on her own? _Yes._ Muttering curses, he decided to set off towards the store anyways. If she were as similar to her brother as she appeared to be, she would just happen to know where the store's exact location was without a guide and he'd find her there already.

How did this happen? Less than 24 hours ago, things were as normal as they could possibly be living with Sherlock, and now it seemed like 221B Baker Street was turned upside down by the arrival of one Ilsa Holmes. He remembered actually wondering if she would be similar to Sherlock. Too smart? Yes. Arrogant? Seemed so. Stubborn? Absolutely. Enjoyed playing mind games? Unfortunately so. And yet, there were some striking differences. First off, she seemed to actually have a grasp on social normalities, even if she _did_ ignore them at John's expense. Fairly friendly. Artistic. She was able to get the best of Sherlock, which was something new to see in itself and, John had to admit, frightened him a great deal. There was also that fact that he was undeniably attracted to her. The way her hips swung as she moved. The way that sweater dress hugged her curves suggestively. Her dark hair against her fair complexion. Those damn blue eyes that were so similar to his flatmate's. She was always two steps ahead of him but waiting for him to catch up. John realized this was not a new sensation, but one that suddenly compelled him in its new, feminine package.

"You really are dense, aren't you?"

John jumped as his reverie was shattered by that high, condescending voice. He spun around to see her standing there in a button up, militaristic styled jacket that he couldn't help but like. "How long have you been following me?" he snapped irritably, shoving his hands in his pockets.

"This entire time, of course," Ilsa answered, slipping an arm around his and giving him that damn innocent look.

For the life of him, he couldn't shake her off even if he wanted to. "That doesn't work on me," John responded matter-of-factually. "I still don't trust you."

"Good!" she giggled as they began walking together. "That makes this much more interesting."

"What is _this?_ I'm not particularly fond of being involved in _this_es. I like to know what's going on, alright? I'm not going to be some game between you and your brother. Got it?" John might not have the willpower to get her off his arm, but he wouldn't let himself be completely used. He wasn't fond of being called malleable earlier. Is that really how they saw him?

To his surprise, Ilsa looked rather wounded by his accusation. "I _told_ you I only waste energy on things I like," she huffed defensively.

John blinked in surprise as the meaning actually sunk in on him. Taken out of context and with the sexual intonation removed...that sounded like an actual compliment. "So...wait. Hold up a minute. You..._aren't_ just hitting on me because I'm your brother's flatmate and it bothers the living hell out of him?"

"That's just a bonus," she insisted. "You were right when you said I was smart, you know. Although, that _is_ pretty obvious. It doesn't take me long to figure out whether or I'm interested in something, which, I'll have you know, isn't very often. You interest me. And I'd have to be a stupid girl to _not_ go after you. Honestly, women these days don't know the first thing about getting what they want when it comes to romance. It's rather pathetic. So, naturally I told you-"

"Do you always talk this much when you're embarrassed?" John cut her off.

Ilsa stiffened on his arm and gawked in his direction like he'd just grown a second head. With a lowered, alarmed voice, she insisted, "I. Am. _Not._ Embarrassed!"

"Well, sure you are," John asserted. "You're being defensive, overly honest, talking yourself up, and trying to separate yourself from other women. Not to mention you're clutching my arm just a bit too tight and the pitch of your voice has risen ever so slightly. I can even tell you're breathing harder. This isn't that difficult to figure out."

Ilsa was quite but looked at him with a new sense of appraisal. "So that's why he likes you," she muttered as she kept her focus away from John and instead slipped off his arm and in front of him into the store. John shrugged and followed after her, certainly a bit confused about what was going on, but feeling a bit better about himself. She might be light years ahead of him mentally, but when it came to romance, John was not one to be bullied. Yes, he wanted her, more than he cared to admit, but he was not just going to roll over for her. If anything was going to come out of this, it was going to be because _he _wanted it and not because she finagled it out of him. At at the current moment, he was deciding it may be for the best to let this one go. Nothing good could come out of relations with his flatmate's sister, let alone a Holmes.

Browsing through the aisles for supplies, Ilsa was quite settled on something else, though.

**Once again, I'd love some reviews! Now things shall begin to heat up~**


End file.
